EXHIBIT 5.1


                  [BROBECK, PHLEGER & HARRISON LLP LETTERHEAD]


Synopsys, Inc.
700 E. Middlefield Road
Mountain View, CA 94043


               Re:  Synopsys, Inc. - Registration Statement for Offering of
                    2,500,000 Shares of Common Stock

Dear Ladies and Gentlemen:

               We have acted as counsel to Synopsys, Inc., a Delaware
corporation (the "Company"), in connection with the registration on Form S-8
(the "Registration Statement") under the Securities Act of 1933, as amended, of
2,500,000 shares of the Company's common stock reserved for issuance under the
Company's 1998 Nonstatutory Stock Option Plan (the "Option Plan").

               This opinion is being furnished in accordance with the
requirements of Item 8 of Form S-8 and Item 601(b)(5)(i) of Regulation S-K.

               We have reviewed the Company's charter documents and the
corporate proceedings taken by the Company in connection with the establishment
and amendment of the Option Plan. Based on such review, we are of the opinion
that, if, as and when the shares of the Company's common stock are issued and
sold (and the consideration therefor received) pursuant to the provisions of
stock option agreements duly authorized under the Option Plan and in accordance
with the Registration Statement, such shares will be duly authorized, legally
issued, fully paid and nonassessable.

               We consent to the filing of this opinion letter as Exhibit 5 to
the Registration Statement.

               This opinion letter is rendered as of the date first written
above and we disclaim any obligation to advise you of facts, circumstances,
events or developments which hereafter may be brought to our attention and which
may alter, affect or modify the opinion expressed herein. Our opinion is
expressly limited to the matters set forth above and we render no opinion,
whether by implication or otherwise, as to any other matters relating to the
Company, the Option Plan or the shares of the Company's common stock issuable
under such plan.

                                        Very truly yours,

                                        /s/ BROBECK, PHLEGER & HARRISON LLP


                                        BROBECK, PHLEGER & HARRISON LLP